Axial pump and hydraulic drive system

ABSTRACT

A hydraulic device having an input shaft and an output shaft, the device comprising: a housing having the input shaft mounted at one end and the output shaft mounted at the other end; an axially reciprocating hydraulic pump mounted on the input shaft within the housing, the axially reciprocating hydraulic pump having: a plurality of pistons located in respective piston bores and configured for axial reciprocation therein; a cam plate connected to the input shaft, the cam plate having a plurality of cam surfaces distributed about the cam plate for driving the plurality of pistons towards Top Dead Center (TDC) of the piston bores; a rotating hydraulic motor mounted on the output shaft within the housing for rotating with the output shaft; and a pair of shared fluid conduits, one of the pair directly and fluidly connecting a fluid outlet of the axially reciprocating hydraulic pump with a fluid inlet of the rotating hydraulic motor and the other of the pair for directly and fluidly connecting a fluid outlet of the rotating hydraulic motor with a fluid inlet of the axially reciprocating hydraulic pump, such that the pair are contained within the housing; wherein flow of hydraulic fluid between the axially reciprocating hydraulic pump and the rotating hydraulic motor bypasses any fluid reservoir external to the housing.

FIELD

The present disclosure relates to piston configurations and hydraulicdevice configurations

BACKGROUND

Paired hydraulic pumps and motors are used predominantly in industrywhen mechanical actuation is desired to convert hydraulic pressure andflow into torque and angular (rotation). Examples of hydraulicapplication can be in braking systems, propulsion systems (e.g.automotive, drilling) as well as in electrical energy generation systems(e.g. windmills). Other common uses of hydraulic devices as a directdrive system can be in drilling rigs, winches and crane drives, wheelmotors for vehicles, cranes, and excavators, conveyor and feeder drives,mixer and agitator drives, roll mills, drum drives for digesters, kilns,trench cutters, high-powered lawn trimmers, and plastic injectionmachines. Further, hydraulic pumps, motors, can be combined intohydraulic drive systems, for example one or more hydraulic pumps coupledto one or more hydraulic motors constituting a hydraulic transmission.

Due to currently available configurations, there exists disadvantageswith hydraulic drive systems. One disadvantage is where the motorhousing is typically distanced from the pump housing and interconnectedvia a series of extended hydraulic lines between the correspondinginlets and outlets. The use of hydraulic lines (e.g. hoses) can resultin system pressure drop resulting in system inefficiencies. A result ofthe use of hydraulic hoses is that the longer distances between pump andmotor via the intervening fluid lines means slower liquid transferbetween the pump and the motor. This can require that the pump be largerthan the motor and can require the pump to operate at higher revolutionsto offset the pressure drop and provide the motor with the required flowto do the work.

Another disadvantage with currently available hydraulic drive systems isthat distanced pump/motor housings can result in pump pistonsstarvation.

A further disadvantage is that off the shelf hydraulic systems are bulkyin design and do not lend themselves easily to applications in compactspaces. As such, the adoption of hydraulic drive systems in energyregeneration has been limited to date. Another disadvantage forcurrently available hydraulic drive systems is that multiplication oftorque at the system output cannot be provided for in an fluidlyefficient and compact form factor due to the number of individualhydraulic devices needed to make up a complete system, as well as themultiplicative effects of pressure losses due to the need forinterconnecting fluid hoses. A further disadvantage is that changing therotational direction of the motor in a hydraulic system can requirestopping of the pump in order to change the direction of the pump andmotor operation, something which is impractical. Current transmissions,including those used with over the road and other commercialapplications, it is common for reverse directions to only have one speedas compared to multiple speeds for the forward direction.

In terms of current axial piston pump configurations, there existsmechanical complications in the design and use of variable anglerotating drive plates (i.e. wobble plate). As such, current axial pistonpump designs tend to have higher than desired maintenance costs andissues, are considered operationally inefficient as compared to otherreciprocating piston pump designs, and more importantly, current axialpiston pumps and motors produce vibration/noise (e.g. Fluidborne noiseand Structuralborne Noise). Considered by the industry as the twoprimary, potentially unsolvable and unwanted problems.

SUMMARY

It is an object of the present invention to provide an axial piston pumpto obviate or mitigate at least some of the above presenteddisadvantages.

It is an object of the present invention to provide a hydraulic drivesystem to obviate or mitigate at least some of the above presenteddisadvantages.

It is an object of the present invention to provide a hydraulic drivemotor to obviate or mitigate at least some of the above presenteddisadvantages.

A first aspect provided is a hydraulic device having an input shaft andan output shaft, the device comprising: a housing having the input shaftmounted at one end and the output shaft mounted at the other end; anaxially reciprocating hydraulic pump mounted on the input shaft withinthe housing, the axially reciprocating hydraulic pump having: aplurality of pistons located in respective piston bores and configuredfor axial reciprocation therein; a cam plate connected to the inputshaft, the cam plate having a plurality of cam surfaces distributedabout the cam plate for driving the plurality of pistons towards TopDead Center (TDC) of the piston bores; a rotating hydraulic motormounted on the output shaft within the housing for rotating with theoutput shaft; and a pair of shared fluid conduits, one of the pairdirectly and fluidly connecting a fluid outlet of the axiallyreciprocating hydraulic pump with a fluid inlet of the rotatinghydraulic motor and the other of the pair for directly and fluidlyconnecting a fluid outlet of the rotating hydraulic motor with a fluidinlet of the axially reciprocating hydraulic pump, such that the pairare contained within the housing; wherein flow of hydraulic fluidbetween the axially reciprocating hydraulic pump and the rotatinghydraulic motor bypasses any fluid reservoir external to the housing.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and other aspects will now be described by way of exampleonly with reference to the attached drawings, in which:

FIG. 1 is a cross sectional view of a piston cylinder arrangement of ahydraulic drive and driven system;

FIG. 2a is a cross sectional view of a rotating cam plate of thehydraulic drive system shown in FIG. 1;

FIG. 2b is a cross sectional view of the rotating cam plate of thehydraulic drive system shown in FIG. 2a with TDC and BDC considerations;

FIG. 3 is an operational example of the hydraulic drive system shown inFIG. 1;

FIG. 4 is a further operational example of the hydraulic drive systemshown in FIG. 1;

FIG. 5 is a still further operational example of the hydraulic drivesystem shown in FIG. 1;

FIG. 6 is still further operational example of the hydraulic drivesystem shown in FIG. 1;

FIG. 7 is still further operational example of the hydraulic drivesystem shown in FIG. 1;

FIG. 8 is still further operational example of the hydraulic drivesystem shown in FIG. 1;

FIG. 9 is an alternative embodiment of the hydraulic drive system shownin FIG. 1; and

FIG. 10 is an operational example of the hydraulic drive system shown inFIG. 9.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Referring to FIG. 1, shown is a hydraulic device 100 having a housing242 enclosing an axial hydraulic pump 101 mounted on shaft 25 (e.g.input shaft driven by an electric motor) supported on bearings 102.Further, the housing 242 also contains one or more hydraulic motors 103(e.g. rotating, vane type) mounted on shaft 24 (e.g. an output shaftconnected to a system to do work such as but not limited to a vehicledrive shaft, a wheel spindle, etc.) supported on bearings 105. It isrecognised that the shaft 24 is mechanically decoupled from the shaft25, thus providing for a direct driving fluidly of the hydraulicmotor(s) 103 by the hydraulic pump 101 and direct supplying fluidly ofthe hydraulic pump 101 by the hydraulic motor(s) 103 within the samehousing 242, as effected by hydraulic fluid inlet and outlet exchangebetween the hydraulic pump 101 and the hydraulic motor(s) 103, asfurther described below. In other words, hydraulic fluid outlet of thehydraulic pump 101 within the housing 242 is directly and fluidlycoupled to hydraulic fluid inlet of the hydraulic motor(s) 103 withinthe housing 242 and hydraulic inlet of the hydraulic pump 101 within thehousing 242 is directly and fluidly coupled to hydraulic outlet of thehydraulic motor(s) 103 within the housing 242, such that directly andfluidly coupled is defined as any hydraulic fluid transfer between thehydraulic pump 101 and the hydraulic motor(s) 103 bypasses entry andexit of any intermediate hydraulic fluid reservoir (not shown)external/internal to the housing 242.

In terms of a hydraulic system provided by the hydraulic device 100,including the fluidly coupled hydraulic pumps 101,107 and hydraulicmotor(s) 103, pressure of the hydraulic fluid 111 entering the hydraulicpump 101,107 is less than the pressure of the hydraulic fluid 111exiting the hydraulic pump 101,107 due to work being performed on thehydraulic fluid 111 by the pistons of the hydraulic pump 101,107.Further, it is recognised that pressure of the hydraulic fluid 111entering the hydraulic motor(s) 103 is greater than the pressure of thehydraulic fluid 111 exiting the hydraulic motor(s) 103 due to work beingperformed on the mechanical components (e.g. inducing rotation of gears,vanes, etc.) of the hydraulic motor(s) 103 by the hydraulic fluid 111.Further, it is recognised that the pressure of the hydraulic fluid 111exiting the hydraulic motor(s) 103 and re-entering the inlet of thehydraulic pump 101,107 is at a pressure greater than atmosphericpressure, due to the fact that the direct and fluid coupling (i.e.shared fluid conduits 35 a,b) there between is unvented. On thecontrary, intermediate hydraulic reservoirs (not shown) of state of theart hydraulic systems are vented to atmosphere and as such, any residualpressure contained in the hydraulic fluid 111 exiting the hydraulicmotor(s) 103 is exhausted via the intermediate hydraulic reservoir.

It is recognised that bypassing of an intermediate hydraulic fluidreservoir (e.g. between the respective inlet/outlets of the hydraulicpump 101,107 and motor(s) 103) for hydraulic fluid exchange between theinlets/outlets of the hydraulic pump 101 and the correspondingoutlets/inlets of the hydraulic motor(s) 103 provides for numerousoperational advantages, as discussed. The hydraulic device 100 can alsooptionally have a regenerative hydraulic pump 107 having a rotating camplate 28 mounted on the shaft 24, such that the regenerative hydraulicpump 107 is coupled fluidly to the hydraulic motor(s) 103 and one ormore hydraulic fluid accumulators 1,46. For certain operatingconditions, it is recognised that the shaft 24 can be the input shaft,for example in regenerative energy applications. It is recognised thatthe device types of the motors 103 and the pump 101 can be different,such that the axial reciprocating device type of the hydraulic pump 101is matched with a rotating device type of the hydraulic motor(s) 103,such that the pump 101 and the motor(s) 103 are mounted on separateshafts 25,24.

Also coupled to the housing 242 via appropriate fluid conduits are thehigh pressure hydraulic fluid accumulator 46 and the low pressurehydraulic fluid accumulator 1, such that resident fluid pressure ofhydraulic fluid in the high pressure hydraulic fluid accumulator 46 isgreater than resident fluid pressure of hydraulic fluid in the lowpressure hydraulic fluid accumulator 1. The high pressure accumulator 46can be used as a source of high pressure hydraulic fluid 111 that can bechanneled through the hydraulic motor(s) 103 and returned to the lowpressure accumulator 1 in order to cause rotation of the shaft 24, asfurther described by example below. The low pressure accumulator 1 canbe used to provide priming hydraulic fluid 111 upon start up of thehydraulic device 100 when valve 3 is open to provide hydraulic fluid 111via line 8 into fluid gallery 9 in order to prime piston bores 11,27with hydraulic fluid 111. Further, piston bores 108,109 can be primedvia fluid gallery 214 with hydraulic fluid 111 from the low pressureaccumulator 1 when valve 3 and valve 213 are opened simultaneously. Alsoprovided can be a hydraulic fluid filter 41 as is known in the art. Alsoprovided can be a series of cooling fins 124 to one side of the housing242 (e.g. adjacent to the shaft 25 of the pump 101 and opposite to thepiston bores 108,109 and/or 11,27), in order to provide forthermodynamic cooling of the hydraulic device 100, when in operation,via cooling fluid (e.g. air) circulating into and out of cooling fan 240(e.g. rotating with shaft 25) via cooling fluid lines 241 (e.g. airpassage) of the housing 242.

The axial hydraulic pump 101 has a plurality of axially reciprocatingpistons 64,65 driven by a cam plate 29 mounted on the shaft 25, the camplate having a plurality of cam lobes distributed about the cam plate29. As the shaft 25 is rotated due to an energy input device coupled tothe shaft 25 (e.g. electric motor, internal combustion engine, etc.—notshown), the cam plate 29 with corresponding cam lobes also rotates withthe shaft 25 to cause advancing cam surfaces 104 to (via a series of camlobes) alternately drive the pistons 64,65 towards Top Dead Center (TDC)of the piston bores 11,27 against any fluid pressure of hydraulic fluid111 present in the piston bores 11,27, thereby facilitating ejection ofhydraulic fluid 111 from the piston bores 64,65. Conversely, the pistons64,65 also travel towards Bottom Dead Center (BDC) of piston bores 64,65under bias of the hydraulic fluid 111 (under pressure) being injectedinto the piston bores 64,65, and stored energy returned by passivepistons, such that piston drive faces 106 remain in contact with theretreating cam surfaces 104 as the cam plate 29 is rotated.

As such, in general, the pistons 64,65 reciprocate in respective bores11,27 as the cam surfaces 104 of respective cam lobes act on pistondrive surfaces 106 of the pistons 64,65, in order to drive the pistons64,65 axially in their respective bores 11,27 towards TDC and to receivethe pistons 64,65 as they are forced towards BDC via the injection ofhydraulic fluid 111 into the piston bores 11,27. The interface betweenthe cam surfaces 104 and the opposing piston drive surfaces 106 is of afloating type, such that absence of appropriate fluid pressure in thepiston bores 11,27 can provide for decoupling (i.e. cam surface 104 isspaced apart in the piston bore(s) 11,27 from the piston drive surface106) between the cam plate 29 and the pistons 64,65 such that thepistons 64,65 can remain at TDC once positioned there due to rotation ofthe cam plate 29, or can remain anywhere between BDC and TDC whenintroduction of hydraulic fluid 111 into the piston bores 11,27 isrestricted via operation of appropriate valves as further describedbelow. Optionally, piston bores 11,27 can be subdivided by floatingpistons 110 acting as a reciprocating piston interface between hydraulicfluid 111 volume and pressure (considered as an incompressible fluid)and compressible fluid (e.g. air) 112 volume and pressure. The volume ofthe compressible fluid 112 on one side of the floating piston 110 can befixed (shown) or variable through an appropriate compressible fluidinlet/outlet port (not shown). It is recognised that pressure of thecompressible fluid 112 to one side of the floating piston 110 isdependent upon the volume of the compressible fluid in the piston bore11,27 as well as the pressure of the hydraulic fluid 111 on the otherside of the floating piston 110.

Application of a driving force by the cam surfaces 104 drives thepistons 64,65 towards TDC of the piston bores 11,27 in order to pumphydraulic fluid 111 resident in the bores 11,27 out through fluidgallery 13, such that fluid gallery 13 of piston bore 11 is in directfluid communication with fluid gallery 13 of piston bore 27. Fluidgallery 13 is considered a fluid outlet for the piston bores 11,27.Further, entry of hydraulic fluid 111 through fluid gallery 9 intopiston bores 11,27 of sufficient pressure and volume acts to drive thepistons 64,65 back towards BDC of the piston bores 11,27, such thatfluid gallery 9 of piston bore 11 is in direct fluid communication withfluid gallery 9 of piston bore 27. In other words, hydraulic fluid 111entering into the piston bores 11,27 via common fluid gallery 9 (i.e.hydraulic fluid inlets of the piston bores 11,27) causes the pistondrive surfaces 106 to be encouraged to follow the rotating cam surfaces104 as the axial pistons 64,65 travel back towards BDC. It is alsorecognised that in the event that the pistons 64,65 are spaced apartfrom the cam lobes of the cam plate 29, i.e. cam surfaces 104 are out ofdirect contact with piston drive surfaces 106, introduction of hydraulicfluid 111 into the piston bores 11,27 will drive the pistons 64,65towards BDC in order to place cam surfaces 104 in direct contact withpiston drive surfaces 106. It is recognised that more than two pistons64,65 and corresponding piston bores 11,27 can be connected to the fluidgalleries 9,13, for example multiple pairs of pistons 64,65 and pistonbores 11,27 distributed about the input shaft 25 as driven by therotating cam plate 29.

Optionally, the axial hydraulic pump 101 and/or the regenerative pump107 can be configured as a double acting pump. Shown is a double actingconfiguration for the pump 101 as an example, such that each of thepistons 64,65 has a corresponding opposing piston 238,243 as desired,however it is recognisd that the regenerative pump 107 could havepistons and bores with appropriate valving and fluid conduits on theother side of the cam plate 28 similar to the arrangement for thepistons 65,64 on the other side of the cam plate 29. In the doubleacting configuration, axial pistons 238,243 reciprocate in correspondingpiston bores 108,109 when acted upon by the cam lobes of the cam plate29, such that pistons 238,243 also have piston drive surfaces 106 of afloating type with corresponding cam surfaces 104 as discussed above. Assuch, the plurality of axially reciprocating pistons 238,243 are drivenby the cam plate 29 mounted on the shaft 25, the cam plate having theplurality of cam lobes distributed about the cam plate 29. As the shaft25 is rotated due to the energy input device coupled to the shaft 25(e.g. electric motor, internal combustion engine, etc.—not shown), thecam plate 29 with corresponding cam lobes also rotates with the shaft 25to cause advancing cam surfaces 104 to (via a series of cam lobes)alternately drive the pistons 238,243 towards TDC of the piston bores108,109 against any fluid pressure of hydraulic fluid 111 present in thepiston bores 108,109, thereby facilitating ejection of hydraulic fluid111 from the piston bores 108,109. Conversely, the pistons 238,243 alsotravel towards BDC of piston bores 108,109 under bias of the hydraulicfluid 111 and pressure being injected into the piston bores 108,109,such that piston drive faces 106 remain in contact with the retreatingcam surfaces 104 as driven by the injection of the hydraulic fluid 111into the piston bores 108,109 under pressure.

Optionally, piston bores 108,109 can be subdivided by floating pistons114 acting as a reciprocating piston interface between hydraulic fluid111 volume and pressure (considered as an incompressible fluid) andcompressible fluid (e.g. air) 112 volume and pressure. The volume of thecompressible fluid 112 on one side of the floating piston 114 can befixed (shown) or variable through an appropriate compressible fluidinlet/outlet port (not shown). It is recognised that pressure of thecompressible fluid 112 to one side of the floating piston 114 isdependent upon the pressure of the hydraulic fluid 111 on the other sideof the floating piston 114. Accordingly, the hydraulic pump 101configured as a double acting pump can have pairs of opposed pistons64,238 or 65,243 operated on by a common intervening cam lobe on therotating cam plate 29, such that the respective pair of cam surfaces 104of the common can lobe are oriented away from one another. In FIG. 1 thecam surface 104 acting on piston 238 is oriented away from the camsurface 104 acting on piston 64 such that the pair of cam surfaces aredirectly opposite to one another (e.g. a linear relative orientation or180 degrees apart). However, it is recognised that this type of camsurface 104 pair orientation shown in FIG. 1 is only by example, asother orientations are possible, such as but not limited to “V” shapedrelative orientations, etc. It is recognised that more than two pistons238,243 and corresponding piston bores 108,109 can be connected to thefluid galleries 214,215, for example multiple pairs of pistons 238,243and piston bores 108,109 distributed about the input shaft 25 as drivenby the rotating cam plate 29.

Application of a driving force by the cam surfaces 104 drives thepistons 238,243 towards TDC of the piston bores 108,109 in order to pumphydraulic fluid 111 resident in the bores 108,109 out through fluidgallery 215, such that fluid gallery 215 of piston bore 108 is in directfluid communication with fluid gallery 215 of piston bore 109. Fluidgallery 215 is considered a fluid outlet for the piston bores 108,109.Further, entry of hydraulic fluid 111 through fluid gallery 214 intopiston bores 108,109 of sufficient pressure and volume acts to drive thepistons 238,243 back towards BDC of the piston bores 108,109, such thatfluid gallery 214 of piston bore 108 is in direct fluid communicationwith fluid gallery 214 of piston bore 109. In other words, hydraulicfluid 111 entering into the piston bores 108,109 via fluid gallery 214(i.e. hydraulic fluid inlets of the piston bores 108,109) causes thepiston drive surfaces 106 to follow the rotating cam surfaces 104 as theaxial pistons 238,243 travel back towards BDC. It is also recognisedthat in the event that the pistons 238,243 are spaced apart from the camlobes of the cam plate 29, i.e. cam surfaces 104 are out of directcontact with piston drive surfaces 106, introduction of hydraulic fluid111 into the piston bores 108,109 will drive the pistons 238,243 towardsBDC in order to place cam surfaces 104 in direct contact with pistondrive surfaces 106.

As such, it is recognised that optionally the rotating cam plate 29 canhave pairs of opposed cam surfaces 104 for each of the cam lobes of thecam plate 29 in order to provide for double acting axial reciprocationof opposed pairs of pistons 64,238 and opposed pairs of pistons 65,243.Preferably each piston of the opposed pairs of pistons 64,238 andopposed pairs of pistons 65,243 travel towards TDC or BDC at the sametime, e.g. piston 64 travels to TDC as piston 238 travels to TDC andpiston 64 travels to BDC as piston 238 travels to BDC in theirrespective piston bores 11,108. As discussed, the orientation of theopposed pairs of pistons 64,238 and opposed pairs of pistons 65,243 canbe other as shown, i.e. other than directly and linearly opposed, forexample opposed in a “V” shape configuration using opposing cam faces104 and/or opposing piston drive faces 106 that are non parallel to oneanother. A cam lobe can be defined as a portion of the cam plate 28,29forming the cam face 104 between successive troughs on the cam plate28,29.

As such, the opposed pairs of pistons 64,238 and 65,243 are positionedon opposite sides of the cam plate 29, as shown in FIG. 2a , such thatpiston bores 11,27 and 108,109 are omitted for clarity. Referring toFIG. 2b , shown are the advancing and retreating cam faces 104interacting with the piston drive faces 106 of the pistons64,65,238,243, resulting in axial displacement of the pistons64,65,238,243 in the respective piston bores 111,27,108,109 between TDCand BDC (i.e. advancing towards TDC and retreating towards BDC) as thepiston drive faces 106 follow the cam faces 104 during axialreciprocation of the pistons 64,65,238,243 in the respective pistonbores 111,27,108,109. It is also recognised that cam plate 28, withrespect to pistons 116,118 and faces 104,106, operates in a similarmanner to that shown in FIGS. 2a,2b for cam plate 29.

The regenerative hydraulic pump 107 has the rotating cam plate 28mounted on the shaft 24 with a plurality of axially reciprocatingpistons 116,118 driven by the cam plate 28 as it rotates. The pistons116,118 reciprocate in respective bores 119,120 as the cam surfaces 104of respective cam lobes act on piston drive surfaces 106 of the pistons116,118, in order to drive the pistons 116,118 axially in theirrespective bores 119,120. The interface between the cam surfaces 104 andthe opposing piston drive surfaces 106 is of a floating type, such thatabsence of appropriate fluid pressure in the piston bores 119,120 canprovide for decoupling (i.e. cam surface 104 is spaced apart in thepiston bore(s) 119,120 from the piston drive surface 106) between thecam plate 28 and the pistons 116,118 such that the pistons 116,118 canremain at TDC once positioned there due to rotation of the cam plate 28,or can remain somewhere between TDC and BDC once the inflow of hydraulicfluid 111 into the piston bores 119,120 is inhibited via appropriateoperation of valves restricting access of the hydraulic fluid 111 intothe piston bores 119,120. Optionally, piston bores 119,120 can besubdivided by floating pistons 122 acting as a reciprocating pistoninterface between hydraulic fluid 111 volume and pressure (considered asan incompressible fluid) and compressible fluid (e.g. air) 112 volumeand pressure. The volume of the compressible fluid 112 on one side ofthe floating piston 122 can be fixed (shown) or variable through anappropriate compressible fluid inlet/outlet port (not shown). It isrecognised that pressure of the compressible fluid 112 to one side ofthe floating piston 122 is dependent upon the volume of the compressiblefluid in the piston bore 119,120 as well as the pressure of thehydraulic fluid 111 on the other side of the floating piston 122.

The axial regenerative hydraulic pump 107 has the plurality of axiallyreciprocating pistons 116,118 driven by the cam plate 28 mounted on theshaft 24, the cam plate having the plurality of cam lobes distributedabout the cam plate 28. As the shaft 24 is rotated (e.g. by rotation ofa vehicle wheel connected to the shaft 24), the cam plate 28 withcorresponding cam lobes also rotates with the shaft 24 to causeadvancing cam surfaces 104 to (via a series of cam lobes) alternatelydrive the pistons 116,118 towards TDC of the piston bores 119,120against any fluid pressure of hydraulic fluid 111 present in the pistonbores 119,120, thereby facilitating ejection of hydraulic fluid 111 fromthe piston bores 119,120. Conversely, the pistons 116,118 also traveltowards BDC of piston bores 119,120 under bias of the hydraulic fluid111 and pressure being injected into the piston bores 119,120, such thatpiston drive faces 106 remain in contact with the retreating camsurfaces 104 as the cam plate 28 rotates. It is recognised that morethan two pistons 116,118 and corresponding piston bores 119,120 can beconnected to the fluid galleries 16,19, for example multiple pairs ofpistons 116,118 and piston bores 119,120 distributed about the outputshaft 24 as driven by the rotating cam plate 28. It is also recognisedthat the number of pistons 116,118 need not match the number of pistons64,65.

Application of a driving force by the cam surfaces 104 drives thepistons 116,118 towards TDC of the piston bores 119,120 in order to pumphydraulic fluid 111 resident in the bores 119,120 out through fluidgallery 19, such that fluid gallery 19 of piston bore 119 is in directfluid communication with fluid gallery 19 of piston bore 120. Fluidgallery 19 is considered a fluid outlet for the piston bores 119,120.Further, entry of hydraulic fluid 111 through fluid gallery 16 intopiston bores 119,120 of sufficient pressure and volume acts to drive thepistons 116,118 back towards BDC of the piston bores 119,120, such thatfluid gallery 16 of piston bore 119 is in direct fluid communicationwith fluid gallery 16 of piston bore 120. In other words, hydraulicfluid 111 entering into the piston bores 119,120 via fluid gallery 16(i.e. hydraulic fluid inlets of the piston bores 119,120) causes thepiston drive surfaces 106 to follow the retreating cam surfaces 104 asthe axial pistons 116,118 travel back towards BDC. It is also recognisedthat in the event that the pistons 116,118 are spaced apart from the camlobes of the cam plate 28, i.e. cam surfaces 104 are out of directcontact with piston drive surfaces 106, introduction of hydraulic fluid111 into the piston bores 119,120 will drive the pistons 116,118 towardsBDC in order to place cam surfaces 104 in direct contact with pistondrive surfaces 106.

The housing 242 contains one or more hydraulic motors 103 (e.g.rotating, vane type) mounted on the shaft 24, such thatinjection/ejection of hydraulic fluid 111 into/out of shared fluidconduits 35 a,35 b provides for pressure and flow induced rotation ofthe hydraulic motors 103. The shared fluid conduits 35 a,35 b in thehousing 242 are positioned between the inlets/outlets of the hydraulicpump 101,107 and the hydraulic motor 103, such that the fluid transferbetween the hydraulic pump 101,107 and the hydraulic motor(s) 103 issuch that they are directly fed by one another via the interposed sharedfluid conduits 35 a,35 b (i.e. pressurized fluid 111 ejected from thepump 101,107 is fed to the motor(s) 103 and expired fluid 111 from themotor(s) 103 is supplied to the pump 101,107). As such, respectiveinlets/outlets of the hydraulic pump 101 (optionally the regenerativehydraulic pump 107) and the hydraulic motor(s) 103 are directly andfluidly coupled by the shared fluid conduits 35 a,b positioned therebetween. In other words, the shared fluid conduits 35 a,35 b can accepthydraulic fluid 111 from the fluid outlet 13,19 of the hydraulic pump(s)101,107 and feed the received hydraulic fluid 111 directly to the fluidinlet (via opened valve(s) 218,219,220,223,222,221) of the hydraulicmotor(s) 103, such that any intermediate fluid reservoir (not shown) isbypassed in transference of the hydraulic fluid 111 between thehydraulic motor(s) 103 and the hydraulic pump 101,107 performed via theshared fluid conduits 35 a,b.

As well, the shared fluid conduits 35 a,35 b can accept hydraulic fluid111 from the fluid outlet (via appropriately opened valve(s)218,219,220,223,222,221) of the hydraulic motors(s) 103 and feed thereceived hydraulic fluid 111 directly to the fluid inlet 9,16 of thehydraulic pump(s) 101,107, such that an intermediate fluid reservoir isbypassed in transference of the hydraulic fluid 111 between thehydraulic motor(s) 103 and the hydraulic pump 101,107 performed via theshared fluid conduits 35 a,b. As such, each shared fluid conduit 35 a,35b has an entrance for accepting hydraulic fluid 111 from thecorresponding fluid outlet of one of the hydraulic motor 103 or thehydraulic pump 101,107 and an exit coupled to the corresponding fluidinlet for delivering the hydraulic fluid 111 from the shared fluidconduit 35 a,b into the corresponding fluid inlet of the other of thehydraulic motor 103 or the hydraulic pump 101,107. It is recognised thatthe shared fluid conduit 35 a,b is not considered a fluid reservoir asthe shared fluid conduit 35 a,b contains pressurized hydraulic fluid 111of the same pressure as hydraulic fluid 111 exiting the hydraulic pump101,107 or hydraulic motor(s) 103. It is also recognised that injectionpressure control of the hydraulic fluid 111 exiting the hydraulicmotor(s) 103 is controlled via pressure control valve 167 beforeintroduction of the hydraulic fluid 111 to the inlet gallery 9,214 ofthe hydraulic pump 101,107. As such, it is recognised that injectionpressure control is implemented between the shared fluid conduits 35 a,bfor fluid flowing from the hydraulic motor(s) 103 towards the hydraulicpump 101,107, such that the pressure of the hydraulic fluid 111 isgreater than atmospheric in order to facilitate a greater operationalefficiency of the hydraulic device 100 as compared to state of the artsystems involving vented fluid reservoirs positioned between the outletsof a hydraulic motor and an inlet of a hydraulic pump coupled to thehydraulic motor.

It is also recognised that utilization of the shared fluid conduits 35a,b positioned within the housing 242 provides for a reduced length offluid conduit extending between both the inlet/outlet and theoutlet/inlet of the hydraulic pump 101,107 and motor(s) 103respectively, as compared to state of the art hydraulic systemsinvolving supply lines between respective housings of the pump and themotor, thus facilitating an advantage of the hydraulic device 100providing reduced hydraulic circuit losses and fluid transit lag ascompared to the state of the art hydraulic systems.

A further advantage is that pressure losses, due to cooling provided byexternal reservoirs used in state of the art hydraulic systems, isinhibited on the hydraulic device 100 due to implementation of thecooling fins 241 provided in the body of the housing 242, such that heattransfer for heat generated in the hydraulic fluid 111 is by firsttransfer to the body (e.g. metal block) of the housing 242 from thehydraulic fluid 111 and then second from the body to atmosphere by thecooling fins 241 and associated cooling fan 240. It is also recognisedthat instead of air used for cooling, fins 241 and fan 240 could beexposed to cooling fluid (e.g. water). Any heat transfer by state of theart hydraulic systems typically involves a heat exchanger that iscoupled to the external reservoir, which is separate from the individualhousings of the pump and motor. As such, heat transfer from thehydraulic fluid for state of the art hydraulic systems relies upontransfer between the fluid and a heat exchanger separate from theindividual housings, as compared to the hydraulic device 100 which hasthe cooling fins 241 (e.g. heat exchanger) in the body of the housing242 in order to take advantage of heat transfer from the hydraulic fluid111 to the material of the housing 242 body, as the hydraulic fluid 111flows within the housing 242 between the hydraulic pump 101,107 and thehydraulic motor(s) 103. Thus it is considered that the hydraulic device100, as configured with shared fluid conduits 35 a,b and cooling fins241 provided by the body of the housing 242 (e.g. as formed by the bodyof the housing 242), provides for increased efficiency advantages influid flow and heat transfer characteristics as compared to state of theart hydraulic systems involving an intermediate fluid reservoir externalto the housings of the hydraulic pump and motor.

It is recognised that a fluid reservoir found in conventional hydraulicsystems, i.e. other than the hydraulic device 100, is a reservoircontaining fluid that is at a reduced pressure (e.g. vented toatmosphere) compared to the exit pressure or entrance pressure of thehydraulic pump/motor connected to the fluid reservoir. In a typicalreservoir of hydraulic systems, fluid is stored in the reservoir, drawnout of the reservoir by a pump at a low pressure and operated on, anddumped into the reservoir by a motor into a fluid pressure dictated byventing requirements of the reservoir. It is also recognised thattypical reservoirs are used for heat transfer considerations, i.e. fluidwhen resident in the reservoir is subjected to cooling (e.g. via adesignated direct/indirect heat exchanger and/or surface cooling). It isalso recognised that reservoirs are exactly that, reservoirs. As suchthe exact fluid entering is not immediately expelled from the reservoirupon entry of the subsequent fluid dumped into the reservoir. As such,fluid when deposited into the reservoir mixes with other fluid alreadycontained in the reservoir and then the fluid experiences a latencyperiod (e.g. reservoir residence time) within the reservoir before beingwithdrawn from the reservoir. Also, given the excess volume capacity ofthe reservoir as compared to the volume of fluid deposits or withdrawalsfrom the bores of hydraulic devices (e.g. pumps/motors) connected to thereservoir, fluid residency practically guarantees that fluid first inwill not be fluid first out of the reservoir. As such, the configurationof the hydraulic fluid outlet 13,19 directly to the fluid inlet of thehydraulic motor(s) 103 via the shared fluid conduit 35 a,b, with thefluid outlet of the hydraulic motor(s) 103 directly connected to thefluid inlet 9,16 of the hydraulic pump 101,107, provides for distinctadvantages of efficiency and compactness of design as compared to moretraditional hydraulic systems having an intervening reservoir betweentheir pump and motor. Further, it is recognised that exit/outletpressure of the hydraulic fluid 111 from the hydraulic pump 101,107 canbe the same, ignoring any frictional pressure losses for interveningvalves/fluid conduits between the inlets/outlets, as the entrance/inletpressure of the hydraulic fluid 111 to the hydraulic motor(s) 103 due tothe configuration and position of the shared fluid conduits 35 a,b withrespect to the hydraulic pump 101,107 and motor(s) 103. Similarly, it isrecognised that exit/outlet pressure of the hydraulic fluid 111 from thehydraulic motor 103 can be the same, ignoring any frictional pressurelosses for intervening valves/fluid conduits between the inlets/outlets,as the entrance/inlet pressure of the hydraulic fluid 111 to thehydraulic pump 101,107 due to the configuration and position of theshared fluid conduits 35 a,d with respect to the hydraulic pump 101,107and motor(s) 103.

It is appreciated that the fluid outlet gallery 13 of the hydraulic pump101 feeds into the shared fluid conduit 35 a or 35 b depending uponwhether valve 43 or valve 33 (e.g. of solenoid type) is open or closed,for example open valve 43 and closed valve 33 (as shown) provides outletgallery 13 to feed shared fluid conduit 35 a by the pump 101, whileclosed valve 43 and open valve 33 (not shown) provides outlet gallery 13to feed shared fluid conduit 35 b by the pump 101, as further discussedbelow. In terms of the regenerative pump 107, open valve 15simultaneously with open valve 43 and closed valve 33 (as shown)provides for feeding of the shared fluid conduit 35 a by theregenerative pump 107, as further discussed below.

Each motor 103 of the one or more hydraulic motors 103 has a controlvalve 218,219,220 for providing transfer (ingress or egress) ofhydraulic fluid between the shared fluid conduit 35 a and each motor103. For example, if shared conduit 35 a is filled with hydraulic fluid111 by the hydraulic pump 101,107, then opening of control valve 218will provide hydraulic fluid 111 under pressure to drive motor A.Similarly, opening of control valve 219 will provide hydraulic fluid 111under pressure to drive motor B. Similarly, opening of control valve 220will provide hydraulic fluid 111 under pressure to drive motor C. Alsorecognised that opening of more than one of the control valves218,219,220 simultaneously will provide for multiple motors A,B,C atonce to be driven by the flow of hydraulic fluid 111 entering and thedirectly exiting the shared fluid conduit 35 a. For example, if sharedconduit 35 b is filled with hydraulic fluid 111 by the hydraulic pump101,107, then opening of control valve 223 will provide hydraulic fluid111 under pressure to drive motor A. Similarly, opening of control valve222 will provide hydraulic fluid 111 under pressure to drive motor B.Similarly, opening of control valve 221 will provide hydraulic fluid 111under pressure to drive motor C. Also recognised that opening of morethan one of the control valves 223,222,221 simultaneously will providefor multiple motors A,B,C at once to be driven by the flow of hydraulicfluid 111 entering and the directly exiting the shared fluid conduit 35b. It is recognised that the entry of hydraulic fluid 111 via valve(s)218,219,220 provides for rotation of the motor(s) 103 in a firstdirection (e.g. clockwise), while entry of hydraulic fluid 111 viavalve(s) 221,222,223 provides for rotation of the motor(s) 103 in seconddirection opposite to the first (e.g. counter clockwise). As such thehydraulic motor(s) 103 of the hydraulic device 100 can be driven in aforward or a reverse direction and as such rotation of the shaft 24 canalso be driven in a first rotational direction or a second rotationaldirection opposite to the first rotational direction. These two oppositerotational directions provides for the hydraulic motor(s) 103 to beoperated in a forward or reverse direction (e.g. meaning able to propela vehicle in a forward or reverse direction when the shaft 24 isconnected to a drive shaft of the vehicle, meaning able to propel adrill bit in a forward or reverse direction when the shaft 24 isconnected to a drive shaft of the drill, etc). As such, the hydraulicdevice 100 can be operated having one or more motors 103 in operation todrive the output shaft 24, based on the number of valve pairs 218,223219,222, 220,221 in an open state. In order for each of the motors A,B,Cto remain lubricated during operation of the motor 103, each of thevalves 218,219,220 or 221,222,223 can be opened at least a fraction inorder to provide for some leakage hydraulic fluid flow through each ofthe motors A,B,C “isolated” from the operational mode of the hydraulicdevice. For example, if motor A is used in operation of the motor 103,then valve 218 is opened (e.g. fully) and then “unused” motors B,C(which are rotating in conjunction with rotation of Motor A) can be fedvia a percentage opening of the valves 219, 220 (e.g. 0.9% open), inorder to provide for motors B,C to remain lubricated during rotation ofthe output shaft 24.

The number of motors 103 selected for operation can depend upon demandconsiderations of a load (e.g. drive shaft for a drill rig, drive shaftfor a motor vehicle, etc.) connected to the output shaft 24, such thatincreased torque requirements of the load could demand a greater numberof the motors 103 in operation as compared to increased speedrequirements of the load could demand a lesser number of the motors 103in operation. In other words, as the torque requirement of the loadincreases, the number of motors 103 in operation could increase (i.e.more valve pairs 218,223 219,222, 220,221 are opened in response to anincreased torque requirement received from the controller 90). In otherwords, as the torque requirement of the load decreases, the number ofmotors 103 in operation could decrease (i.e. more valve pairs 218,223219,222, 220,221 are closed in response to a decreased torquerequirement received from the controller 90).

It is recognised that the various control valves can be automatic aspressure driven (e.g. check valves such as those valves in FIG. 1 shownbetween piston bore 11,27 and fluid galleries 9,13, between shared fluidconduits 35 a,b, between piston bores 108,109 and fluid galleries 214,215 and between piston bores 119,120 and fluid galleries 16,19) and/orcan be electronically controlled valves (e.g. valves 3, 15, 33, 43, 54,59, 213, 218, 219, 220, 221, 222, 223, 234, 235, 236, 237, 238)controlled by the electronic controller 90 (e.g. containing a processorand memory to execute a set of stored instructions to operate thecontrol valves in sequence to effect operation of the hydraulic device100 for flow of hydraulic fluid 111 to and from the hydraulic motor(s)103, to and from the hydraulic pump 101,107, and to and from the lowpressure accumulator 1 and to and from the high pressure accumulator 46)as providing electronic signals 92 to cause a change in operationalstate of the control valves, e.g. from valve close to valve open or fromvalve open to valve close in response to receipt of the control signal).As such, operation of the hydraulic device 100 is effected by operationof the valves as shown. It is also recognised that directed flow of thehydraulic fluid 111 into and out of the selected fluid conduits 8, 38,39, 42, 44, 60, 61, 69, 77 is used to determine the manner in which thehydraulic fluid 111 enters and exits the shared fluid conduits 35 a,b aswell as the accumulators 1,46, as directed by the operational state ofthe valves as discussed herein.

Referring to FIGS. 1 and 3, side A of the main pump using reciprocationof pistons 64,65 in bores 11,27 to drive the hydraulic motor 103. Atstep 300, valves 3, 43, 54, 59 are opened by the controller 90 sendingopen signals 92, while valves 4, 237, 213, 15, 33, 55, 236, 235, 234,246, 250, 252, 254, 256 are held or otherwise operated closed by thecontroller 90. In terms of motor 103 selection, at least one of thevalve pairs 218,223, 219,222, 220,221 are opened by the controller 90via signals 92 in order to facilitate hydraulic fluid 111 flow into andout of the selected hydraulic motor(s) A,B,C via shared fluid conduits35 a,b. Once the valves are set by the controller 90, this provides for,at step 302, hydraulic fluid 111 to be released from the low pressureaccumulator 1 along conduit 8 and into fluid inlet gallery 9 in order toprime the piston bores 11,27. At step 304, reciprocation of input shaft25 rotates cam plate 29 to cause the advancing cam surfaces 104 to drivepistons 64,65 to pump hydraulic fluid 111 out of piston bores 11,27 viafluid outlets gallery 13 and into shared conduit 35 a, as the pistons64,65 approach TDC, via open solenoid valve 43. At step 306, hydraulicfluid 111 deposited into shared fluid conduit 35 a enters one or moreselected hydraulic motor(s) A,B,C and causes the output shaft 24 torotate in a first direction (e.g. forward direction for a vehicle, drillbit, etc. attached to the output shaft 24). At step 308, hydraulic fluiddeposited into shared conduit 35 b after doing work via the selectedhydraulic motor(s) A,B,C enters fluid conduit 39 through valve 54, thenthrough conduit 61, through fluid filter 41, into conduit 77 and throughvalve 59 in order to access and enter fluid inlet gallery 9, realizingthat the injection pressure of the hydraulic fluid into the fluidgalleries 9 is regulated by a pressure control valve (PCV) 167 in fluidconduit 69 which facilitates excess hydraulic fluid to be deposited fromfluid conduit 69 and back to the shared conduit(s) 35 a,b via fluidconduits 49 and 50 coupled thereto. Check valves in fluid conduit 50provide for entrance of the hydraulic fluid 111 into the shared conduits35 a,b. At step 310, hydraulic fluid entering piston bores 11,27 forcethe pistons 64,65 against the cam faces 104 to then follow theretreating cam surface 104 as the cam plate rotates on shaft 25 as thepistons 64,65 travel back towards BDC of the piston bores 11,27. At step312, continued rotation of the input shaft 25 causes the above describedcirculation of the hydraulic fluid 111 to repeat to continue to operatethe selected hydraulic motor(s) A,B,C. It is recognised that since valve213 is closed, side B of the main pump (i.e. pistons 238,243) remainsunprimed and thus piston drive face 106 becomes decoupled from cam faces104 in the piston bores 108,109 as the cam plate 29 rotates, thusinhibiting injection/ejection of hydraulic fluid 111 with respect to thepiston bores 108,109 as the input shaft 25 rotates. Similarly, sincevalve 15 is closed, the regenerative pump 107 (i.e. pistons 116,118)remains fluidly isolated from the shared conduits 35 a,b and thus pistondrive face 106 becomes decoupled from cam faces 104 of rotating camplate 28 in the piston bores 119,120 as the cam plate 28 rotates on theoutput shaft 24, thus inhibiting injection/ejection of hydraulic fluid111 with respect to the piston bores 119,120 as the output shaft 24rotates.

Referring again to FIG. 3, in the event that the double acting abilityof the hydraulic device 100 is desired, controller 90 sends openactuation signal 92 to valve 213 to be open at step 400, thus providingfor hydraulic fluid 111 at step 314 to be released from the low pressureaccumulator 1 along conduit 8 and into fluid inlet gallery 214 in orderto prime the piston bores 108,109 as well as piston bores 11,27, thusproviding for a double acting hydraulic pump operation. Further at step304, reciprocation of input shaft 25 rotates cam plate 29 to cause theadvancing cam surfaces 104 to drive pistons 238,243 to pump hydraulicfluid 111 out of piston bores 108,109 via fluid outlets gallery 215,into fluid conduits 216, 60, deposited into fluid inlet gallery 9 andthen into shared conduit 35 a via piston bores 11,27, as the pistons238,243 also approach TDC, via open solenoid valve 43. Step 306 is doneas per above to have at step 316 hydraulic fluid be deposited fromconduit 77, into fluid gallery 9 and then via open valve 213 in fluidconduit 8 in order to access and enter fluid inlet gallery 214 of sideB, realizing that the injection pressure of the hydraulic fluid into thefluid galleries 214 is regulated by a pressure control valve (PCV) 167in fluid conduit 69. At step 318, hydraulic fluid 111 also enteringpiston bores 108,109 when returning from the motor(s) A,B,C force thepistons 238,243 against the cam faces 104 to then follow the retreatingcam surface 104 as the cam plate rotates on shaft 25 as the pistons238,243 travel back towards BDC of the piston bores 108,109. At step312, continued rotation of the input shaft 25 causes the above describedcirculation of the hydraulic fluid 111 to repeat to continue to operatethe selected hydraulic motor(s) A,B,C under the influence of the doubleacting configuration of the hydraulic pump 101 (i.e. using both sides Aand B of the main pump 101) in order to rotate the output shaft 24.

Referring to FIGS. 1 and 4, side A of the main pump using reciprocationof pistons 64,65 in bores 11,27 to drive the hydraulic motor 103. Atstep 400, valves 3, 33 55, 59, 54, 256 are opened by the controller 90sending open signals 92, while valves 4, 237, 213, 15, 43, 236, 235,246, 250, 252, 254, 234, are held or otherwise operated closed by thecontroller 90. In terms of motor 103 selection, at least one or more ofthe valve pairs 218,223, 219,222, 220,221 are opened by the controller90 via signals 92 in order to facilitate hydraulic fluid 111 flow intoand out of the selected hydraulic motor(s) A,B,C via shared fluidconduits 35 a,b. Once the valves are set by the controller 90, thisprovides for, at step 402, hydraulic fluid 111 to be released from thelow pressure accumulator 1 along conduit 8 and into fluid inlet gallery9 in order to prime the piston bores 11,27. At step 404, reciprocationof input shaft 25 (in a same shaft 25 direction as for rotation of themotor(s) A,B,C as described above) rotates cam plate 29 to cause theadvancing cam surfaces 104 to drive pistons 64,65 to pump hydraulicfluid 111 out of piston bores 11,27 via fluid outlets gallery 13 andinto shared conduit 35 b, as the pistons 64,65 approach TDC, via opensolenoid valve 33 opposite to closed solenoid valve 43. At step 406,hydraulic fluid 111 deposited into shared fluid conduit 35 b enters oneor more selected hydraulic motor(s) A,B,C and causes the output shaft torotate in a second direction opposite the first direction (e.g. reversedirection for a vehicle, drill bit, etc. attached to the output shaft25). At step 408, hydraulic fluid 111 deposited into shared conduit 35 aafter doing work via the selected hydraulic motor(s) A,B,C enters fluidconduit 38 through valve 55, then through conduit 62, through fluidfilter 41, into conduit 77 and through valve 59 in order to access andenter fluid inlet gallery 9, realizing that the injection pressure ofthe hydraulic fluid into the fluid galleries 9 is regulated by apressure control valve (PCV) 167 in fluid conduit 69 which facilitatesexcess hydraulic fluid to be deposited from fluid conduit 69 and back tothe shared conduit(s) 35 a,b via fluid conduits 49 and 50 coupledthereto. At step 410, hydraulic fluid 111 entering piston bores 11,27force the pistons 64,65 against the cam faces 104 to then follow theretreating cam surface 104 as the cam plate rotates on shaft 25 as thepistons 64,65 travel back towards BDC of the piston bores 11,27. At step412, continued rotation of the input shaft 25 causes the above describedcirculation of the hydraulic fluid 11 to repeat to continue to operatethe selected hydraulic motor(s) A,B,C. It is recognised that since valve213 is closed, side B of the main pump (i.e. pistons 238,243) remainsunprimed and thus piston drive face 106 becomes decoupled from cam faces104 in the piston bores 108,109 as the cam plate 29 rotates, thusinhibiting injection/ejection of hydraulic fluid 111 with respect to thepiston bores 108,109 as the input shaft 25 rotates. Similarly, sincevalve 15 is closed, the regenerative pump 107 (i.e. pistons 116,118)remains fluidly isolated from the shared conduits 35 a,b and thus pistondrive face 106 becomes decoupled from cam faces 104 of rotating camplate 28 in the piston bores 119,120 as the cam plate 28 rotates on theoutput shaft 24, thus inhibiting injection/ejection of hydraulic fluid111 with respect to the piston bores 119,120 as the output shaft 24rotates.

Referring again to FIG. 4, in the event that the double acting abilityof the hydraulic device 100 is desired, controller 90 sends openactuation signal 92 to valve 213 to be open at step 400, thus providingfor hydraulic fluid 111 at step 414 to be released from the low pressureaccumulator 1 along conduit 8 and into fluid inlet gallery 214 in orderto prime the piston bores 108,109 as well as piston bores 11,27 viagallery 9, thus providing for a double acting hydraulic pump operationfor operating the motor(s) A,B,C in the second direction. Further atstep 404, reciprocation of input shaft 25 rotates cam plate 29 to causethe advancing cam surfaces 104 to drive pistons 238,243 to pumphydraulic fluid 111 out of piston bores 108,109 via fluid outletsgallery 215, into fluid conduits 216,60, deposited into fluid inletgallery 9 and then into shared conduit 35 b via piston bores 11,27, asthe pistons 238,243 also approach TDC, via open solenoid valve 33. Step406 is done as per above to have at step 416 hydraulic fluid bedeposited from conduit 77, into fluid gallery 9 and then via open valve213 in fluid conduit 8 in order to access and enter fluid inlet gallery214 of side B, realizing that the injection pressure of the hydraulicfluid into the fluid galleries 214 is regulated by a pressure controlvalve (PCV) 167 in fluid conduit 69. At step 418, hydraulic fluid 111also entering piston bores 108,109 when returning from the motor(s)A,B,C force the pistons 238,243 against the cam faces 104 to then followthe retreating cam surface 104 as the cam plate rotates on shaft 25 asthe pistons 238,243 travel back towards BDC of the piston bores 108,109.At step 412, continued rotation of the input shaft 25 causes the abovedescribed circulation of the hydraulic fluid 111 to repeat to continueto operate the selected hydraulic motor(s) A,B,C under the influence ofthe double acting configuration of the hydraulic pump 101 (i.e. usingboth sides A and B of the main pump 101) in order to rotate the outputshaft 24 in the second direction.

As per above, it is recognised that operation of the hydraulic motor(s)A,B,C, in both the forward (a first direction) and the reverse (in asecond direction opposite the first direction) rotational directions, isfacilitates by selecting one or more motor(s) A,B,C from a cluster ofmotors contained in the hydraulic motor 103. In other words, simulationof a hydraulic transmission in both forward and reverse directions canbe accommodated for by the hydraulic device 100 based on selection ofthe appropriate valving (e.g. one or the other of the solenoid valves43,33 to facilitate the shared conduits 35 a,b being used in an 35 a to35 b or a 35 b to a 35 a direction) along with the appropriate number ofmotors A,B,C via selection of one or more valve pairs 218,223, 219,222,220,221 opened by the controller 90 via signals 92. In other words,opening of multiple valve pairs 218,223, 219,222, 220,221 simultaneouslyprovides for multiple motors A,B,C to be operated (i.e. rotated) at thesame time based on the same flow of hydraulic fluid 111 provided fromand to the hydraulic pump 101 via the shared fluid conduits 35 a,b. Itis also recognised that open/close state of the pair of solenoid valves43,33 provides for either: 1) using the shared fluid conduit 35 a as themotor 103 fluid inlet and the shared fluid conduit 35 b as the motor 103fluid outlet; or 2) the shared fluid conduit 35 b as the motor 103 fluidinlet and the shared fluid conduit 35 a as the motor 103 fluid outlet.Swapping use of the shared fluid conduits 35 a,b as either inlets oroutlets provides the advantage of operating the hydraulic motor(s) A,B,Cin either the first direction or the second direction to provide forcorresponding rotation of the output shaft 24 in either the firstdirection or the second direction, while the input shaft 25 maintainsits rotation in the same direction for both the first direction or thesecond direction of the output shaft 24.

Referring to FIGS. 1 and 5, regenerative pump 107 using reciprocation ofpistons 116,118 in bores 119,120 to drive the hydraulic fluid 111 fromthe low pressure accumulator 1 to the high pressure accumulator 46. Atstep 500, valves 4, 15, 54, 55, 234, 236, 256 are opened by thecontroller 90 sending open signals 92, while valves 3, 213, 237, 235,48, 43, 33, 59, 167, 246, 252, 250, 254 are held or otherwise operatedclosed by the controller 90. Once the valves are set by the controller90, this provides for, at step 502, hydraulic fluid 111 to be releasedfrom the low pressure accumulator 1 along conduit 44 and into fluidinlet gallery 16 via valve 15 in order to prime the piston bores119,120, thereby forcing pistons 116,118 towards BDC. At step 504, asthe pistons 116,118 travel towards BDC, piston drive faces 106 actagainst cam surface 104 in piston bores 119,120. At step 506,reciprocation of output shaft 24 (in view of mechanical/kinetic energyinput from vehicle wheels attached to the output shaft, etc.) rotatescam plate 28 to cause the advancing cam surfaces 104 to drive pistons116,118 to pump hydraulic fluid 111 out of piston bores 119,120 viafluid outlet gallery 19 and into shared conduit 35 a,b via fluid conduit38, as the pistons 116,118 approach TDC at step 506 (noting fluidisolation of main hydraulic pump 101 maintained via closed solenoidvalve 33 opposite to closed solenoid valve 43 and check valves on theoutside of gallery 13). Also it is noted that the hydraulic motors A,B,Care isolated from the hydraulic circuit, however hydraulic fluid 111still has access to either side 35 a,b of the hydraulic motors A,B,C viafluid conduit 38 and associated check valves in order to keep the motorsA,B,C lubricated as the output shaft 24 is rotated. At step 508,hydraulic fluid 111 deposited into shared fluid conduit 35 a,b bypassesone or more selected hydraulic motor(s) A,B,C and flows out throughvalves 54,55 and into fluid conduit 77, such that in regenerative mode,all solenoid valves relating to motors A,B,C in-out flow should be leftopen so that all motors A,B,C get lubricated. At step 510, hydraulicfluid 111 enters fluid conduit 69 and through valve 236 in order to bedeposited into the high pressure accumulator 46. Thus continuedinjection of hydraulic fluid 111 at step 512 from the low pressureaccumulator 1 into the regenerative pump 107 repeats at step 502 inorder to use continued mechanical/kinetic energy transferred to shaft 24(via external mechanical system such as rotating vehicle wheels—notshown—connected to the shaft 24) acting as an input shaft under energyregeneration conditions (e.g. using momentum of the vehicle connected tothe shaft 24 to pump hydraulic fluid 111 from the low pressureaccumulator 1 to the high pressure accumulator 46), while operation ofmain pump 101 and the motors A,B,C remains fluidly isolated from thehydraulic circuit as per above (i.e. are isolated from doing work on thehydraulic fluid as the hydraulic fluid is circulated through theregenerative pump 107 in travelling from the low pressure accumulator 1to the high pressure accumulator 46.

Referring to FIGS. 1 and 6, driving the hydraulic motor 103 is performedwhile the regenerative pump 107 and the main pump 101,103 remain fluidlyisolated whereby respective cam faces 104 and opposed piston drive faces106 can become decoupled. At step 600, valves 48, 54, 235, 237, 256 areopened by the controller 90 sending open signals 92, while valves 236,43, 33, 15, 55, 59, 167, 234, 3, 426, 250, 252, 254, 213, 4 are held orotherwise operated closed by the controller 90. In terms of motor 103selection, at least one or more of the valve pairs 218,223, 219,222,220,221 are opened by the controller 90 via signals 92 in order tofacilitate hydraulic fluid 111 flow into and out of the selectedhydraulic motor(s) A,B,C via shared fluid conduits 35 a,b. Once thevalves are set by the controller 90, this provides, at step 602,hydraulic fluid 111 to be released from the high pressure accumulator 46as stored energy and into and out of the motor A,B,C via through openvalve 48, into conduit 42, and into shared fluid conduit 35 a. At step604, hydraulic fluid 111 deposited into shared fluid conduit 35 a entersone or more selected hydraulic motor(s) A,B,C and causes the motor(s)A,B,C to rotate in order to drive the attached output shaft 24. At step606, hydraulic fluid 111 is deposited into shared conduit 35 b afterdoing work via the selected hydraulic motor(s) A,B,C and enters fluidconduit 39 through valve 54, through fluid conduit 61, through filter41, into conduits 77,69 and through valves 235,237 in order to bedeposited into the low pressure accumulator 1. At step 608, continuedsupply of hydraulic fluid out of the HP accumulator 46 provides forcontinued rotation of the output shaft 24 via stored energy release,thus transferring from the HP accumulator 46 to the LP accumulator 1.

Referring to FIGS. 1 and 7, driving the hydraulic motor 103 isperformed, while only the regenerative pump 107 and side B of the mainpump 101 remain fluidly isolated whereby respective cam faces 104 andopposed piston drive faces 106 can become decoupled. At step 700, valves43, 54, 48, 59, 235, 237, 3, 4, 256 (note 167 can also be used at thistime to control the injection pressure into the main pump 101) areopened by the controller 90 sending open signals 92, while valves 3, 15,33, 55, 234, 236, 213, 246, 250, 252, 254, are held or otherwiseoperated closed by the controller 90. In terms of motor 103 selection,at least one or more of the valve pairs 218,223, 219,222, 220,221 areopened by the controller 90 via signals 92 in order to facilitatehydraulic fluid 111 flow into and out of the selected hydraulic motor(s)A,B,C via shared fluid conduits 35 a,b. Once the valves are set by thecontroller 90, this provides for, at step 702, hydraulic fluid 111primes pistons 64,65 of the main pump A as per above along with travelinto and out of the motor(s) A,B,C as per steps 302,304,306,308,310,312of FIG. 3. Simultaneously at step 704, fluid travels from the HPaccumulator 46 through the motor(s) A,B,C to the LP accumulator 1 as persteps 602,604,608 of FIG. 6. It is also recognised that the injectionpressure of the hydraulic fluid 111 into the fluid galleries 9 isregulated by the pressure control valve (PCV) 167 in fluid conduit 69which facilitates excess hydraulic fluid to be deposited from fluidconduit 69 and back to the shared conduit(s) 35 a,b via fluid conduits49 and 50 coupled thereto. It is also recognised that some of theflowing hydraulic fluid 111 will remain within the motor pump circuit(via shared fluid conduits 35 a,b) while any excess volume of thehydraulic fluid 111 is directed to the LP accumulator 1 via conduit 69and valves 235, 237.

Referring to FIGS. 1 and 7, driving the hydraulic motor 103 isperformed, while only the regenerative pump 107 remains fluidly isolatedwhereby respective cam faces 104 and opposed piston drive faces 106 canbecome decoupled. At step 700, valves 3, 43, 54, 48, 59, 213, 235, 237,256 (note 167 can also be used at this time to control the injectionpressure into the main pump 101) are opened by the controller 90 sendingopen signals 92, while valves 15, 33, 55, 234, 236, 246, 250, 252, 254,are held or otherwise operated closed by the controller 90. In terms ofmotor 103 selection, at least one or more of the valve pairs 218,223,219,222, 220,221 are opened by the controller 90 via signals 92 in orderto facilitate hydraulic fluid 111 flow into and out of the selectedhydraulic motor(s) A,B,C via shared fluid conduits 35 a,b. Once thevalves are set by the controller 90, this provides for, at step 706 foroperating the side B pump (e.g. double acting mode) is donesimultaneously with steps 702 and 704. Sub steps 314, 316,318 areperformed in step 706 as described above for FIG. 3. It is alsorecognised that the injection pressure of the hydraulic fluid 111 intothe fluid galleries 9 is regulated by the pressure control valve (PCV)167 in fluid conduit 69 which facilitates excess hydraulic fluid to bedeposited from fluid conduit 69 and back to the shared conduit(s) 35 a,bvia fluid conduits 49 and 50 coupled thereto. It is also recognised thatsome of the flowing hydraulic fluid 111 will remain within the motorpump circuit (via shared fluid conduits 35 a,b) while any excess volumeof the hydraulic fluid 111 is directed to the LP accumulator 1 viaconduit 69 and valves 235,237.

Referring to FIGS. 1 and 8, storing energy during engine idle of amechanical system (e.g. Internal Combustion Engine idle connected toinput shaft 25) is performed, while only the regenerative pump 107 andside B of the main pump 101 remain fluidly isolated (noting the motorsA,B,C can also be isolated given there is no rotation of same) wherebyrespective cam faces 104 and opposed piston drive faces 106 can becomedecoupled. At step 800, valves 3, 234, 235, 236 are opened by thecontroller 90 sending open signals 92, while valves 237, 213, 48, 33,43, 15, 59, 4, 54, 55, 250, 252, 254, 256, 246 are held or otherwiseoperated closed by the controller 90. Once the valves are set by thecontroller 90, this provides for, at step 802, hydraulic fluid 111 to bereleased from the low pressure accumulator 1 along conduit 8 and intofluid inlet gallery 9 in order to prime the piston bores 11,27. At step804, reciprocation of input shaft 25 rotates cam plate 29 to cause theadvancing cam surfaces 104 to drive pistons 64,65 to pump hydraulicfluid 111 out of piston bores 11,27 via fluid outlets gallery 13 andinto fluid conduit 44 (bypassing shared conduit 35 a as valves 43,33 areclose in order to fluidly isolate hydraulic motor(s) A,B,C), as thepistons 64,65 approach TDC. At step 806, hydraulic fluid 111 enters intothe HP accumulator 46 via open valves 234,235,236. At step 808, repeatedinjection of hydraulic fluid 111 at step 802 causes continued transfervia the main pump A of hydraulic fluid 111 from the LP accumulator 1. Itis also recognised that the pressure of the hydraulic fluid 111 isregulated by the pressure control valve (PCV) 167. It is noted thatinjection pressure can also be regulated by valve 3 which could be a PCVfor example.

Referring to FIGS. 1 and 8, storing kinetic energy during idle of amechanical system (e.g. Internal Combustion Engine idle connected toinput shaft 25) is performed, while only the regenerative pump 107remains fluidly isolated (and also isolation of the motors A,B,C)whereby respective cam faces 104 and opposed piston drive faces 106 canbecome decoupled. At step 800, valves 3, 213, 234, 235, 236 are openedby the controller 90 sending open signals 92, while valves 237, 15, 33,43, 48, 4, 59, 54, 55, 256, 246, 250, 252, 254 are held or otherwiseoperated closed by the controller 90 and 167 controls injectionpressure. Once the valves are set by the controller 90, this providesfor, at step 810 hydraulic fluid 111 to be released from the lowpressure accumulator 1 along conduit 8 and into fluid inlet gallery 9 aswell as into fluid gallery 214 in order to prime the piston bores108,109 along with piston bores 11,27, thus providing for double actingoperation. At step 812 in conjunction with step 804, reciprocation ofinput shaft 25 rotates cam plate 29 to cause the advancing cam surfaces104 to drive pistons 238,243 to pump hydraulic fluid 111 out of pistonbores 108,109 via fluid outlets gallery 215 and into fluid conduit 216and into fluid inlet gallery 9 via piston bores 11,27 to fluid outletgallery 13 and into fluid conduit 44 (bypassing shared conduit 35 a,b asvalves 43,33 are closed in order to fluidly isolate hydraulic motor(s)A,B,C), as the pistons 238,243 approach TDC. At step 806, hydraulicfluid 111 enters into the HP accumulator 46 via open valves 234,235,236.At step 808, repeated injection of hydraulic fluid 111 at step 802causes continued transfer via the pump A,B of main pump 101 of hydraulicfluid 111 from the LP accumulator 1. It is also recognised that thepressure of the hydraulic fluid 111 is regulated by the pressure controlvalve (PCV) 167 and 3.

It is recognised that filling of the HP accumulator 46 during engineidle conditions provides for the hydraulic device 100 to output somestorable energy while using the idling engine or the like. This storageability at idle is also an advantage as it allows for the HP accumulator46 to be filled towards capacity and then used as stored energy combinedwith the continuous energy obtained from normal operation of thehydraulic pump 101 and hydraulic motor 103 to provide a momentary powerboost at the motor output shaft 24, when desired as controlled by thecontroller 90.

Referring to FIGS. 1 and 9 and 10, controller 90 via signals 92 canselect which of the pistons 238,243 and/or 64,65, and/or 116,118 areused to assist in braking of the vehicle (not shown) connected to theoutput shaft 24 (e.g. drive shaft and/or wheel spindles) and optionallyconnected to the input shaft 25 (e.g. coupled to an engine—e.g. ICE—ofthe vehicle). As such in this example, the engine or power plant of thevehicle is used to drive the vehicle wheels under normal operation (ortrack system in the case of a track vehicle) in order to propel thevehicle along a surface (e.g. roadway, railway tracks, etc.) supportingthe vehicle. As such, the first rotational direction of the output shaft24 can be referred to as a forward direction for the vehicle and thesecond rotational direction can be referred to as a reverse direction ofthe vehicle.

The hydraulic device 100 can also have a fluid conduit 245 associatedwith a pressure control valve 246 connected to the fluid circuit of thehydraulic device 100 between the valve 236 and the HP accumulator 46.Pressure control/relief valve 246 operates such that when input pressureof the hydraulic fluid 111 reaches a predetermined maximum pressure whenpassing through valve 236, this is an indication that the HP accumulator46 is considered full and cannot accept any more hydraulic fluid 111. Assuch, once the HP accumulator 46 becomes filled (e.g. cannot accept anyfurther hydraulic fluid 111), utilization of the hydraulic device 100 toprovide braking horsepower for the vehicle is as provided below wherehydraulic fluid flowing through valve 236 is directed through thepressure control valve 246 and into fluid conduit 245 directinghydraulic fluid away from the HP accumulator 46. It is recognized thatwhen pressure in accumulator 46 reaches a predetermined maximum, valve236 may not see max pressure from the system as there needs to be a headto have pressure as discussed.

The fluid conduit 245 is coupled to fluid conduit 77 via valve 250, tofluid conduit 60 via control valve 252 and to fluid inlet gallery 16 viacontrol valve 254. Positioned in series with fluid conduit 245 can be afluid cooler lines CL1 and/or a fluid cooler lines CL2 (e.g. (e.g. heattransfer device provided by the fins 241 in the body of the housing 242as acted upon by the cooling fan 240), used to extract heat from thehydraulic fluid 111 flowing through the pressure control valve 246introduced due to a pressure drop experienced by the hydraulic fluid 111when passing there through, i.e. temperature of the hydraulic fluid 111on the inlet side of the pressure control valve 246 is lower than thetemperature of the hydraulic fluid 111 on the outlet side of thepressure control valve 246. Also provided is a control valve 256 influid conduit 69.

In terms of facilitating engine braking (i.e. use of hydraulic pump 101coupled to input shaft 25) in combination with regenerative braking(i.e. use of regenerative pump 107 coupled to the output shaft 24),pistons 64,65 and pistons 238,243 can be employed in the hydraulicdevice 100 to perform work on the hydraulic fluid 111, thus transferringpotential engine brake HP from the engine of the vehicle via the inputshaft 25 along with output shaft 24 brake HP in the form of heatgeneration via the pressure control valve 246. In order to implementthis braking mode, a linkage 240 (see FIG. 1) can be engaged by thecontrol unit 90 (via an engagement signal) between the input 25 andoutput 24 shafts, such that engagement of the linkage 240 results in acoupling (e.g. mechanical, hydraulic, etc.) between the shafts 24,25 tofacilitate their co-rotation. Once the braking mode is completed (e.g.braking is no longer required), the control unit can send adisengagement signal to the linkage 240 in order to decouple the shafts24,25. It is recognized that that the linkage 240 can be configured tohave the shafts 24,25 co-rotate at the same RPM or can be configured tohave the shafts 24,25 co-rotate at different RPMs. In any event, it isrecognized that coupling of the shafts 24,25 together by linkage 240effectively puts the engine in direct communication with any loadconnected to the output shaft 24 (e.g. wheels). One example is amechanical linkage 240 optionally involving one or more gears, such thatthe mechanical clutch linkage 240 can be engaged by the control unit 90to couple the shafts 24,25 to one another or can be disengaged by thecontrol unit 90 to decouple the shafts 24,25 to one another. One exampleis a hydraulic clutch linkage 240, such that the hydraulic clutchlinkage 240 can be engaged by the control unit 90 to couple the shafts24,25 to one another or can be disengaged by the control unit 90 todecouple the shafts 24,25 to one another. It is recognized that a normaloperating mode of the hydraulic unit 100 can be where the shafts 24,25are decoupled from one another, except in the case of braking asdescribed.

This type of braking can be for a less sustained or shorter termbraking, such as desiring a decrease in speed of the vehicle due to aslow down or stop event (e.g. braking due to potential collision,braking to stop, etc.), recognizing that the use of the regenerativepump 107 as part of the hydraulic circuit provides for lubrication ofthe hydraulic motors A,B,C while isolating the hydraulic motors A,B,C interms of performing work on the hydraulic fluid 111 (see descriptionassociated with FIG. 5 above). Referring to FIG. 10, at step 900, valves4,15,234,236,246,256,54,55,254 are opened by the controller 90 sendingopen signals 92, while valves 3,252,43,33,59,48,250,213,235,237 are heldor otherwise operated closed by the controller 90. As such, thecontroller 90 is used to select the main A pump and the regenerativepump 107 to circuit the hydraulic fluid 111 while isolating the main Bpump and the hydraulic motor(s) 103 from the hydraulic circuit used incirculating hydraulic fluid 111 through the fluid conduit 245. As such,at step 902 a load such as an engine coupled to the input shaft 25 alongwith the load (e.g. wheels) connect to the output shaft 24 is used toprovide for engine braking via transfer of engine power transmittedthrough input shaft 25 with load/wheel braking via output shaft 24 intoheat via circulation of the hydraulic fluid 111 through the pressurecontrol valve 246 and into fluid conduit 245. At steps 904 and 912,hydraulic fluid 111 is circulated through the cooling lines CL1,CL2 todissipate the generated heat from the hydraulic fluid 111. At steps 906and 914 the hydraulic fluid 111 is circulated through valve 252 and backinto the fluid inlet gallery 9 of the main pump A for further operationby the pistons 64,65 and into the fluid inlet gallery 16 of theregenerative pump 107 for further operation by the pistons 116,118 andcirculation back through the pressure control valve 246.

In terms of facilitating engine braking (i.e. use of hydraulic pump 101coupled to input shaft 25) in combination with regenerative braking(i.e. use of regenerative pump 107 coupled to the output shaft 24),pistons 64,65 and pistons 238,243,116,118 can be employed in thehydraulic device 100 to do work on the hydraulic fluid 111, thustransferring potential engine brake HP from the engine of the vehiclevia the input shaft 25 along with output shaft 24 brake HP in the formof heat generation via the pressure control valve 246. In order toimplement this braking mode, a linkage 240 (see FIG. 1) can be engagedby the control unit 90 (via an engagement signal) between the input 25and output 24 shafts, such that engagement of the linkage 240 results ina coupling (e.g. mechanical, hydraulic, etc.) between the shafts 24,25to facilitate their co-rotation. Once the braking mode is completed(e.g. braking is no longer required), the control unit can send adisengagement signal to the linkage 240 in order to decouple the shafts24,25. This type of braking can be for a less sustained or shorter termbraking, such as desiring a greater decrease in speed of the vehicle dueto a slow down or stop event (e.g. braking due to potential collision,braking to stop, etc.), recognizing that the use of the regenerativepump 107 as part of the hydraulic circuit provides for lubrication ofthe hydraulic motors A,B,C while isolating the hydraulic motors A,B,C interms of performing work on the hydraulic fluid 111 (see descriptionassociated with FIG. 5 above). Referring to FIG. 10, at step 900, valves4,15,54, 55, 246, 256, 254, 234, 236 are opened by the controller 90sending open signals 92, while valves 3,33, 43, 48, 59, 250, 213, 237,252, 235 are held or otherwise operated closed by the controller 90. Assuch, the controller 90 is used to select the main A pump and the main Bpump and the regenerative pump 107 to circulate the hydraulic fluid 111while isolating the main B pump and the hydraulic motor(s) 103 from thehydraulic circuit used in circulating hydraulic fluid 111 through thefluid conduit 245. As such, at step 902 a load such as an engine coupledto the input shaft 25 along with the load (e.g. wheels) connect to theoutput shaft 24 is used to provide for engine braking via transfer ofengine power transmitted through input shaft 25 with load/wheel brakingvia output shaft 24 into heat via circulation of the hydraulic fluid 111through the pressure control valve 246 and into fluid conduit 245. Atsteps 904 and 912, hydraulic fluid 111 is circulated through the coolinglines CL1,CL2 to dissipate the generated heat from the hydraulic fluid111. At steps 906 and 914 the hydraulic fluid 111 is circulated throughvalve 252 and back into the fluid inlet gallery 9 of the main pump A andinto the fluid inlet gallery 214 of the main pump B for furtheroperation by the pistons 64,65,238,243 and into the fluid inlet gallery16 of the regenerative pump 107 for further operation by the pistons116,118 and circulation back through the pressure control valve 246.

In terms of facilitating wheel or track braking (i.e. use of hydraulicpump 107 coupled to output shaft 24), pistons 116,118 can be employed inthe hydraulic device 100 to do work on the hydraulic fluid 111, thustransferring wheel brake HP from the wheels of the vehicle via theoutput shaft 24 to the hydraulic fluid 111 in the form of heatgeneration via the pressure control valve 246. In order to implementthis braking mode, a linkage 240 (see FIG. 1) can be disengaged betweenthe input 25 and output 24 shafts, such that disengagement of thelinkage 240 results in a decoupling between the shafts 24,25 tofacilitate their co-rotation. This type of braking can be for a moresustained or longer term braking, such as driving at a somewhat constantspeed (but not limited to) by the vehicle down a decline. Referring toFIG. 10, at step 900, valves 4,15,234,236,246,55,54,256,254 are openedby the controller 90 sending open signals 92, while valves 43, 33, 59,48, 250, 213, 235, 237, 3, 252 are held or otherwise operated closed bythe controller 90. As such, the controller 90 is used to select theregenerative pump 107 to flow the hydraulic fluid 111, maintaininglubrication of the hydraulic motor(s) 103, while isolating the hydraulicpump 101 (i.e. decoupling driving of pistons 64,65,238,243 from theinput shaft 25) from the hydraulic circuit used in circulating hydraulicfluid 111 through the fluid conduit 245. As such, at step 910 the loadsuch as an wheels coupled to the output shaft 24 is used to provide forwheel braking via transfer of wheel power transmitted through outputshaft 24 into heat via circulation of the hydraulic fluid 111 throughthe pressure control valve 246 and into fluid conduit 245. At step 912,the hydraulic fluid 111 is circulated through the cooling lines CL1,CL2to dissipate the generated heat from the hydraulic fluid 111, whilerealizing that any fluid entering and exiting the motor(s) 103 isdeposited into the fluid conduit 245, such that valves 246, 250 are offto force flow up fluid conduit 69 past 256, 236 and finally 246. At step914 the hydraulic fluid 111 is circulated through valve 254 and backinto the fluid inlet gallery 16 of the regenerative pump 107 for furtheroperation by the reciprocating pistons 116,118, and circulation backthrough the pressure control valve 246 via fluid outlet gallery 19 andfluid conduit 42 through control valve 48.

In view of the above, it is recognised that the controller 90 canconfigure via selection of appropriate valving whether to engage: 1)load on the shafts 24, 25 for generating and dissipating heat via thehydraulic fluid 111 circulation to effect load (e.g. engine and wheels)braking via a single/double acting use of the main pump 101 and theregenerative pump 107; and 2) load on the output shaft 24 for generatingand dissipating heat via the hydraulic fluid 111 circulation to effectload (e.g. wheel) braking via a the regenerative pump 107.

It is recognized that the linkage 240 can be used in a number of modesother than in the braking modes as discussed above. It is recognizedthat the linkage 240 is positioned between the two cam plates 28,29 inorder to couple the shafts 24,25 to one another for co-rotation. Oneadvantage for engagement of the linkage 240 is for connecting the engine(via input shaft 25) as direct mechanical connection to the load (e.g.wheels) via the output shaft 24. Once engaged, the valves as providedabove can be operated by the controller 90 to isolate (from thehydraulic circuit) operation of the main pump 101 and/or theregenerative pump 107 while the shafts 24,25 are directly coupled viathe linkage 240. This provides for driving of the output shaft 24directly via the input shaft 25, for example in the event of pump 101,107 failure (or one of the hydraulic lines coupled thereto). Anotheradvantage is in the case where the accumulator 46 becomes full and thusthe load of the engine coupled to the input shaft 25 can be used. Oneadvantage here is that the hydraulic circuit can be used to provide aportion of the brake horsepower and the engine can be used to providethe other portion of the brake horsepower during vehicle braking events.It is recognized that once the operation involving coupling of bothshafts 24,25 is completed, the controller 90 can disengage (i.e.decouple) the linkage 240 via the signals as desired.

1. A hydraulic device having an input shaft and an output shaft, thedevice comprising: a housing having the input shaft mounted at one endand the output shaft mounted at the other end; an axially reciprocatinghydraulic pump mounted on the input shaft within the housing, theaxially reciprocating hydraulic pump having: a plurality of pistonslocated in respective piston bores and configured for axialreciprocation therein; a cam plate connected to the input shaft, the camplate having a plurality of cam surfaces distributed about the cam platefor driving the plurality of pistons towards Top Dead Center (TDC) ofthe piston bores; a rotating hydraulic motor mounted on the output shaftwithin the housing for rotating with the output shaft; and a pair ofshared fluid conduits, one of the pair directly and fluidly connecting afluid outlet of the axially reciprocating hydraulic pump with a fluidinlet of the rotating hydraulic motor and the other of the pair fordirectly and fluidly connecting a fluid outlet of the rotating hydraulicmotor with a fluid inlet of the axially reciprocating hydraulic pump,such that the pair are contained within the housing; wherein flow ofhydraulic fluid between the axially reciprocating hydraulic pump and therotating hydraulic motor bypasses any fluid reservoir external to thehousing.
 2. The device of claim 1, wherein the cam plate is connected tothe input shaft at a fixed angle to the input shaft.
 3. The device ofclaim 1, wherein the other of the pair is fluidly connected to a secondfluid conduit connecting the other of the pair to the fluid inlet of thehydraulic pump, the second fluid conduit located within a shell of thehousing between the fluid inlet of the hydraulic pump and the fluidoutlet of the hydraulic motor.
 4. The device of claim 1, wherein thefluid inlet of the hydraulic pump and the fluid outlet of the hydraulicmotor are located within the shell of the housing.
 5. The device ofclaim 1, wherein each of the cam surfaces is opposite to a respectivedrive piston surface of each of the plurality of pistons, such that thecam surfaces and the drive piston surfaces can become decoupled from oneanother in a spaced apart manner based on an amount of the hydraulicfluid contained within the piston bores.
 6. The device of claim 1,wherein the amount of the hydraulic fluid injected into a selectedpiston bore of the piston bores can be inhibited via closing of a valveassociated with a fluid line connected to the fluid inlet of theselected piston bore in order to inhibit axial reciprocation of thepiston in the selected piston bore while maintaining an open state of asecond valve associated with a second fluid line connected to the fluidinlet of a second piston bore of the piston bores in order to maintainaxial reciprocation of a second piston in the second piston bore.
 7. Thedevice of claim 1, further comprising a second set of pistons located ina second set piston bores and configured for axial reciprocationtherein, second set of pistons opposed to the plurality of pistons toprovide for configuration of the hydraulic pump as a double acting pump,such that the cam plate has a second set of cam surfaces distributedabout the cam plate opposite the plurality of cam surfaces, the secondset of cam surfaces for driving the plurality of pistons towards TDC ofthe second set of piston bores, fluid outlets of the second set ofpiston bores fluidly coupled to the one of the pair and fluid outlets ofthe second set of piston bores fluidly coupled to the other of the pair.8. The device of claim 1, further comprising a set of control valves forinhibiting injection of the hydraulic fluid into the fluid inlets of thesecond set of piston bores to provide for operation of the hydraulicpump as a single acting pump.
 9. The device of claim 1, furthercomprising a third set of pistons positioned in a corresponding set ofpiston bores in the housing a cam plate connected to the input shaft,the cam plate having a plurality of cam surfaces distributed about thecam plate for driving the plurality of pistons towards Top Dead Center(TDC) of the piston bores.
 10. The device of claim 1, wherein the outputshaft and the input shaft are decoupled from one another and thus freeto rotate independently with respect to one another.
 11. The device ofclaim 1, further comprising a linkage for coupling the output shaft tothe input shaft to facilitate a braking mode.